Cyclic behaviour of clay stabilised with fly-ash based geopolymer incorporating ground granulated slag

In recent years, fly-ash based geopolymers have been an alternate binder to ordinary Portland cement commonly used for soil stabilization, as they were found to enhance soil strength and stiffness with the benefits of entailing lower toxic pollution and energy usage. However, most available studies on geopolymer-stabilised soils have focussed on the mechanical performance of treated soils under static loading rather than cyclic/dynamic loading, which requires further research. This paper investigates the cyclic/dynamic loading behaviour of geopolymer-treated kaolin clay using triaxial tests performed under stress-controlled conditions and range of amplitudes and frequencies. The results indicate that the inclusion of geopolymer considerably enhances the cyclic performance of treated clay in terms of soil attainable accumulated strain, number of load cycles and cyclic shear modulus. Although it is found that a small amount of geopolymer can enhance the initial cyclic response, a larger quantity of geopolymer is necessary to maintain sufficient durability for treated clay over successive loading cycles. However, the enhanced cyclic response of treated clay appeared to be influenced by the increase in stress intensity and applied frequency. It is concluded from this study that geopolymer-treated clay may be suitable to support cyclic loading systems subjected to low loading amplitudes and frequencies such as roads and railways.